Bump akka and blockmanager timeouts to 60 seconds
Merge pull request #642 from pwendell/branch-0.7

Bump akka and blockmanager timeouts to 60 seconds (branch 0.7 backport)
Merge remote-tracking branch 'shivaram/spark-ml-examples' into ml-examples
Removed dependency on Apache Commons Math
Initial implementation of Alternating Least Squares.

Includes unit tests and sample data to run on.
Remove unused import
Some small fixes to ALS.
Scaffolding and model for K-means
Renamed "als" package to "recommendation"
Added a SparkContext accessor to RDD
Formatting
Implementation of k-means and k-means||
Merge remote-tracking branch 'shivaram/spark-ml-examples' into ml-examples
Fix logistic regression test failure and test suite cleanup
Allow RDD.takeSample to give samples bigger than the RDD

Before, when withReplacement was set to true, we would not get a sample
bigger than the RDD's count().
Added unit test for K-means, and fixed some bugs
Use random seeds for K-means and ALS, and increase tolerance in tests

Random seeds make more sense by default for a machine learning library
because other libraries behave the same way (people expect to be able to
run the algorithm multiple times and get a better answer), but we can
add configuration later if needed. Tests that depend on specific seed
choices seem brittle.